Compiler hangs on recursive HRTB

[Nadrieril]

I tried this code:

pub trait LendingIteratorItem<'item> {
    type Item;
}

impl<'item, F> LendingIteratorItem<'item> for (F,)
where
    F: for<'a> FnMut(<Self as LendingIteratorItem<'a>>::Item),
{
    type Item = ();
}

On this code, rustc hangs and slowly eats all my memory. If I change (F,) to F, at least I get "overflow evaluating the requirement" before it eats all my memory. A bunch of other simplifications all error with "overflow evaluating the requirement".

Meta

rustc --version --verbose:

rustc 1.81.0-nightly (f8e566053 2024-06-14)
binary: rustc
commit-hash: f8e566053207b4ecbcbc7a7d6ded82c43061e3da
commit-date: 2024-06-14
host: x86_64-unknown-linux-gnu
release: 1.81.0-nightly
LLVM version: 18.1.7

[matthiaskrgr]

is this a duplicate / code from #108826 (comment) ?

[Nadrieril]

Ah yep, looks similar